Numerous kinds of robotic vehicles have been developed and are being used to traverse duct systems for the purpose of performing any of a wide variety of tasks. For example, a robotic vehicle may be equipped with cleaning apparatus suitable for cleaning the inside surfaces of the duct. Alternatively, the vehicle may be fitted with a small camera to allow for the visual inspection of the duct system from a remote location. In still other applications, the vehicle may be equipped with ultrasonic or other sensors to ascertain the structural integrity of the duct system.
Regardless of the particular task that is to be performed, most robotic vehicles utilize wheels or track drive assemblies to move the vehicles through the duct systems. Unfortunately, however, while such wheeled or tracked vehicles tend to work well, they are often limited to use in duct systems having specific geometries and sizes. For example, a robotic vehicle designed to traverse duct systems having flat floor sections (e.g., duct systems having square or rectangular cross-sections) usually cannot be used in duct systems having curved floor sections (i.e., duct systems having circular or elliptical cross-sections), and vice-versa. Moreover, a vehicle designed to traverse duct systems having curved floor sections is usually limited to duct systems falling within certain size ranges (e.g., circular duct systems having diameters in the range of 8-10 inches or having diameters in the range of 14-18 inches). Consequently, it is usually necessary to use a separate robotic vehicle for each different type of duct geometry and/or size range.
Partly in an effort to avoid the need to utilize a separate, specially designed vehicle for each different duct geometry and size range, vehicle reconfiguration systems have been developed which allow a single robotic vehicle to be specially configured to operate in duct systems having different sizes and geometries. A common type of reconfiguration system utilizes a plurality of special adapters or attachments that may be used to change the configuration of the robotic vehicle: A first set of adapters or attachments may allow the vehicle to traverse ducts having rectangular cross-sections, while another set of adapters or attachments may allow the vehicle to traverse ducts having circular cross-sections.
While such vehicle reconfiguration systems are useful in that they allow a single vehicle to be used in duct systems having different sizes and geometries, they are still not without their problems. For example, the adapters or attachments generally limit the vehicle to operation to one type of duct geometry (e.g., rectangular or circular) at a time, thus requiring the vehicle to be manually reconfigured with a different set of adapters or attachments before it can be used in another type of duct geometry. Moreover, the adapters or attachments that allow the vehicle to traverse duct systems having circular cross-sections usually allow the vehicle to effectively traverse only those duct systems that fall within a relatively small size range. That is, an adapter system may limit the vehicle to use in circular duct systems having diameters in the range of 8-10 inches or having diameters in the range of 14-18 inches. Consequently, vehicles utilizing such reconfiguration systems are still limited in that they cannot readily accommodate variations in duct size and geometry.
Therefore, a need exists for a robotic vehicle for traversing duct systems that can readily accommodate variations in duct size and/or geometry. Ideally, such a system should be capable of reconfiguring the vehicle "on the fly" so that the vehicle can adapt to changes in duct size and geometry that may occur in a single duct system. Additional advantages could be realized if such a reconfiguration system were relatively compact, allowing the vehicle to be made as small as possible, thus allowing it to be used in systems having relatively small duct sizes.